Different policy scenarios to promote various targets of biodiversity

Abstract Biodiversity loss in farmlands is widely documented, and agriculture intensification has been identified as a main driver of this decline. Numerous agri-environmental policies have been implemented to assess the negative impacts of agricultural intensification on biodiversity. However, most published studies focus on land-use scenarios, thus neglecting the economic dimension. We develop a bio-economic spatially explicit modelling across 620 small French agricultural areas, which couples a public decision maker under budgetary constraint, regional economic agents in a context of uncertainty and breeding bird dynamics. Using dynamic models, we analyse the direct impacts of several current economic scenarios of the Common Agriculture Policy on common bird communities through five ecological indicators, all related to breeding populations of birds in farmlands: the farmland bird index (FBI), a generalist bird index (GBI), the Shannon diversity index, a community specialization index (CSI) and a community trophic index (CTI). We consider these indicators to scan various functional traits of bird communities. Trends in the different indicators are significantly contrasted pending on economic policy scenarios. Scenarios promoting intensive crops lead to small but specialized communities with more granivorous species, hence a low trophic level for the community. By contrast, promoting extensive grasslands increases the population size, enhances high trophic level but decreases community specialization. Evaluation of agricultural policies should not rely on a single indicator per taxonomic group. In the context of potential reversal of current bird declines, bio-economic modelling, involving farmland incomes, is proposed as a relevant support for decision making about sustainable agri-environmental policies. Promoting extensive grasslands is essential for the sustainable management of bird communities and agriculture. We, however, reveal more complex economic effects and synergies between public incentives, which appear to give interesting leverage for enhancing the bio-economic effectiveness of agricultural policies.

[1]  A. Cropper.  Convention on Biological Diversity , 1993, Environmental Conservation.

[2]  F. Jiguet,et al.  Functional biotic homogenization of bird communities in disturbed landscapes , 2008 .

[3]  O. Solbrig,et al.  Biodiversity and Global Change. , 1994 .

[4]  Tom Gavin,et al.  Biodiversity in Agricultural Landscapes: Saving Natural Capital without Losing Interest , 2006, Conservation biology : the journal of the Society for Conservation Biology.

[5]  Ross Cullen,et al.  Integrating Economics into Priority Setting and Evaluation in Conservation Management , 2003 .

[6]  P. Fleury,et al.  Agriculture et biodiversité : valoriser les synergies : expertise scientifique collective INRA juillet 2008 , 2009 .

[7]  M. Thomas,et al.  Natural enemy diversity and pest control: patterns of pest emergence with agricultural intensification. , 2002 .

[8]  B. Münier,et al.  Combined ecological and economic modelling in agricultural land use scenarios , 2004 .

[9]  Péter Batáry,et al.  Grassland versus non-grassland bird abundance and diversity in managed grasslands: local, landscape and regional scale effects , 2007, Biodiversity and Conservation.

[10]  S. Polasky,et al.  Agricultural sustainability and intensive production practices , 2002, Nature.

[11]  J. Lamarque,et al.  Global Biodiversity: Indicators of Recent Declines , 2010, Science.

[12]  Frédéric Jiguet,et al.  Low‐intensity agriculture increases farmland bird abundances in France , 2010 .

[13]  R. Beverton,et al.  On the dynamics of exploited fish populations , 1993, Reviews in Fish Biology and Fisheries.

[14]  S. Lavorel,et al.  Agriculture et biodiversité. Valoriser les synergies , 2008 .

[15]  Denis Couvet,et al.  Spatial segregation of specialists and generalists in bird communities. , 2006, Ecology letters.

[16]  Frédéric Jiguet,et al.  Method learning caused a first‐time observer effect in a newly started breeding bird survey , 2009 .

[17]  John R. Krebs,et al.  The second Silent Spring? , 1999, Nature.

[18]  Matthias Albrecht,et al.  The Swiss agri-environment scheme enhances pollinator diversity and plant reproductive success in nearby intensively managed farmland , 2007 .

[19]  Andrew R. Watkinson,et al.  Editors' Introduction: Birds and Agriculture , 2000 .

[20]  Richard B. Bradbury,et al.  The role of agri-environment schemes and farm management practices in reversing the decline of farmland birds in England , 2004 .

[21]  F. Herzog,et al.  Mixed biodiversity benefits of agri-environment schemes in five European countries. , 2006, Ecology letters.

[22]  H.F.M. ten Berge,et al.  Farming options for The Netherlands explored by multi-objective modelling , 2000 .

[23]  S. Butler,et al.  Farmland Biodiversity and the Footprint of Agriculture , 2007, Science.

[24]  D. Kleijn,et al.  The conservation effects of meadow bird agreements on farmland in Zeeland, The Netherlands, in the period 1989–1995 , 2004 .

[25]  H. Levrel,et al.  Enhancing citizen contributions to biodiversity science and public policy , 2008 .

[26]  T. Benton,et al.  Farmland biodiversity: is habitat heterogeneity the key? , 2003 .

[27]  Ruud B.M. Huirne,et al.  Ecological-economic modelling to support multi-objective policy making: a farming systems approach implemented for Tuscany , 2004 .

[28]  D. Pauly,et al.  Fishing down marine food webs , 1998, Science.

[29]  R. Bunce,et al.  Changes in the abundance of farmland birds in relation to the timing of agricultural intensification in England and Wales , 2000 .

[30]  S. Carpenter,et al.  Stability and Diversity of Ecosystems , 2007, Science.

[31]  F. Jiguet,et al.  Common birds facing global changes: what makes a species at risk? , 2004 .

[32]  Taylor H. Ricketts,et al.  The Convention on Biological Diversity's 2010 Target , 2005, Science.

[33]  F. Jiguet,et al.  Bio economic modeling for a sustainable management of biodiversity in agricultural lands , 2011 .

[34]  I. Seidl,et al.  Expert Estimates about Effects of Biodiversity on Ecosystem Processes and Services , 1999 .

[35]  M. Morecroft,et al.  Effects of agri-environment schemes in a long-term ecological time series , 2009 .

[36]  M. Altieri.  The ecological role of biodiversity in agroecosystems , 1999 .

[37]  K. McCann.  The diversity–stability debate , 2000, Nature.

[38]  Modelling the European Farmland Bird Indicator in response to forecast land-use change in Europe , 2011 .

[39]  Non-parametric estimation of decision makers’ risk aversion , 2002 .

[40]  F. Jiguet,et al.  An Indicator of the Impact of Climatic Change on European Bird Populations , 2009, PloS one.

[41]  Paul R. Ehrlich,et al.  Ecosystem consequences of bird declines , 2004, Proceedings of the National Academy of Sciences of the United States of America.

[42]  P. Donald,et al.  Further evidence of continent-wide impacts of agricultural intensification on European farmland birds, 1990–2000 , 2006 .

[43]  R. Green,et al.  Agricultural intensification and the collapse of Europe's farmland bird populations , 2001, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[44]  F. Jiguet,et al.  Bird population trends are linearly affected by climate change along species thermal ranges , 2010, Proceedings of the Royal Society B: Biological Sciences.

[45]  Kate E. Jones,et al.  Impacts of biodiversity on the emergence and transmission of infectious diseases , 2010, Nature.